Time
Time is a metaphysical dimension of our known universe, which is percieved or not percieved in an unlimited number of ways by each individual of what we call life. Time is used to sequence events, to compare the durations of events and the intervals between them, and to quantify the motions of objects. Time is a major subject of religion, philosophy, and science, but defining time in a non-controversial manner applicable to all fields of study consistently eludes the greatest scholars. In physics and other sciences, time is considered one of the few fundamental quantities. p. 17. "I only add to this the observation that relativity and quantum mechanics provide, in string theory, units of length and time which look, at present, more fundamental than any other." Time is used to define other quantites – such as velocity – and defining time in terms of such quantities would result in circularity of definition.Duff, Okun, Veneziano, ibid. p. 3. "There is no well established terminology for the fundamental constants of Nature. … The absence of accurately defined terms or the uses (i.e. actually misuses) of ill-defined terms lead to confusion and proliferation of wrong statements." An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, has a high utility value in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called space-time brings the nature of time into association with related questions into the nature of space, questions that have their roots in the works of early students of natural philosophy. Among philosophers, there are two distinct viewpoints on time. One view is that time is part of the fundamental structure of the universe, a in which events occur in sequence. Sir Isaac Newton subscribed to this [[Philosophical realism|realist] view, and hence it is sometimes referred to as Newtonian time. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is not itself some thing and therefore is not to be measured. Temporal measurement has occupied scientists and technologists, and was a prime motivation in astronomy . Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second , is defined as a certain number of hyperfine transitions in caesium atoms. Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human lifespans. Temporal measurement Temporal measurement, or chronometry, takes two distinct primary forms. The calendar, a mathematical abstraction for calculating extensive periods of time, and the clock, a concrete mechanism that counts the ongoing passage of time. In day-to-day life, the clock is consulted for periods less than a day, the calendar, for periods longer than a day. Time in philosophy In Book 11 of St. Augustine's Confessions, he ruminates on the nature of time, asking, "What then is time? If no one asks me, I know: if I wish to explain it to one that asketh, I know not." He settles on time being defined more by what it is not than what it is.St. Augustine, Confessions, Book 11. http://ccat.sas.upenn.edu/jod/augustine/Pusey/book11 (Accessed 5/26/07). Isaac Newton believed time and space form a container for events, which is as real as the objects it contains. Translated by I. Bernard Cohen and Anne Whitman, University of California Press, Berkeley, 1999.}} In contrast to Newton's belief in absolute space, and a precursor to Kantian time, Leibniz believed that time and space are relational.Gottfried Martin, Kant's Metaphysics and Theory of Science The differences between Leibniz's and Newton's interpretations came to a head in the famous Leibniz-Clarke Correspondence. Leibniz thought of time as a fundamental part of an abstract conceptual framework, together with space and number, within which we sequence events, quantify their duration, and compare the motions of objects. In this view, time does not refer to any kind of entity that "flows," that objects "move through," or that is a "container" for events. Immanuel Kant, in the Critique of Pure Reason, described time as an a priori intuition that allows us (together with the other a priori intuition, space) to comprehend sense experience. translated by J. M. D. Meiklejohn, eBooks@Adelaide, 2004 - http://ebooks.adelaide.edu.au/k/kant/immanuel/k16p/k16p15.html With Kant, neither space nor time are conceived as substances, but rather both are elements of a systematic mental framework necessarily structuring the experiences of any rational agent, or observing subject. Spatial measurements are used to quantify how far apart objects are, and temporal measurements are used to quantify how far apart events occur. In Existentialism, time is considered fundamental to the question of being, in particular by the philosopher Martin Heidegger. See Ontology. Henri Bergson believed that time was neither a real homogeneous medium nor a mental construct, but possesses what he referred to as Duration. Duration, in Bergson's view, was creativity and memory as an essential component of reality.Bergson, Henri (1907) Creative Evolution. trans. by Arthur Mitchell. Mineola: Dover, 1998. Time as "unreal" In 5th century BC Greece, Antiphon the Sophist, in a fragment preserved from his chief work On Truth held that: "Time is not a reality (hypostasis), but a concept (noêma) or a measure (metron)." Parmenides went further, maintaining that time, motion, and change were illusions, leading to the paradoxes of his follower Zeno. Time as illusion is also a common theme in Buddhist thought, and some modern philosophers have carried on with this theme. J. M. E. McTaggart's 1908 The Unreality of Time, for example, argues that time is unreal (see also The flow of time). However, these arguments often center around what it means for something to be "real". Modern physicists generally consider time to be as "real" as space, though others such as Julian Barbour in his The End of Time argue that quantum equations of the universe take their true form when expressed in the timeless configuration spacerealm containing every possible "Now" or momentary configuration of the universe, which he terms 'platonia'. (See also: Eternalism (philosophy of time).) Use of time In sociology and anthropology, time discipline is the general name given to social and economic rules, conventions, customs, and expectations governing the measurement of time, the social currency and awareness of time measurements, and people's expectations concerning the observance of these customs by others. The use of time is an important issue in understanding human behaviour, education, and travel behaviour. Time use research is a developing field of study. The question concerns how time is allocated across a number of activities (such as time spent at home, at work, shopping, etc.). Time use changes with technology, as the television or the Internet created new opportunities to use time in different ways. However, some aspects of time use are relatively stable over long periods of time, such as the amount of time spent traveling to work, which despite major changes in transport, has been observed to be about 20-30 minutes one-way for a large number of cities over a long period of time. This has led to the disputed time budget hypothesis. Time management is the organization of tasks or events by first estimating how much time a task will take to be completed, when it must be completed, and then adjusting events that would interfere with its completion so that completion is reached in the appropriate amount of time. Calendars and day planners are common examples of time management tools. Arlie Russell Hochschild and Norbert Elias have written on the use of time from a sociological perspective. See also *Anachronistic displacement *Autobiographical memory *Biological rhythms *Chronobiology *Chronesthesia *Future *Interresponse time *Intertemporal choice *Mental chronometry *Postponement of affect *Seasonal variations *Sense of time *Temporal discounting *Time disorientation *Time inconsistency *Time management *Time perception *Time preference *Trends References